The discovery of this story could spark speculation as to whether the Leonardo DiCaprio-Kate Winslet 1997 on-screen romance was modelled on this real-life story, especially James Cameron’s depiction of protagonist Jack Dawson.

Like Dawson, Portaluppi got on the Titanic in the last minute and was asked to join first-class passengers for dinner on the night the ill-fated liner hit the iceberg.

The artist, who died aged 93 in 1974, never revealed the true extent of his connection with Mrs Astor. However, interviews he gave in his later life reveal he had a crush on the wealthy American traveller, according to news.discovery.com

A documentary to be aired on the Italian version of the History Channel will tell the story of 37 Italians aboard the Titanic, most of whom were third-class passengers. Only Portaluppi and two others survived.

A talented stonemason, Portaluppi had worked on the reliefs of the New York Stock Exchange Building. The Titanic survivor was returning to Milford, New Hampshire after visiting his family in Italy.

He had originally been booked onto one of the White Star line's other ships, Oceanic II. However, he received a telegram from the Astors inviting him to join them on the Titanic as they returned from a holiday in Egypt, the Discovery website says.

Claudio Bossi author of a book entitled Titanic, told Discovery News: “Only in the last years of his life, when he returned to Italy, he told the tale of his Titanic journey to local journalists.”